A waste gas generated from incineration facilities for incinerating wastes such as industrial wastes and domestic refuse contains various types of chlorinated organic compound such as dioxins, coplanar PCBs, and further polychlorobiphenyl, chlorophenol and chlorobenzene.
Here, the word, dioxins, is a general term of polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofuran (PCDFs), and the like and as known well, they are extremely toxic environmental pollutants and especially tetrachlorodibenzodioxins (T4CDDs) among them is known as the most intensely toxic environmental pollutant. Further, polychlorobiphenyls are also strongly toxic environmental pollutants and coplanar PCBs among them is recognized similarly as the most intensely toxic environmental pollutant. On the other hand, although chlorinated organic compounds such as chlorophenol, chlorobenzene and the like are less toxic than dioxins, they are recognized as environmental pollutants just like dioxins since they are found easy to be converted into dioxins using various element contained in fly ashes as catalyst in, for example, an incinerator in a temperature range of the waste gas. For that, in terms of the environmental preservation, it becomes an urgent issue to establish a countermeasure for removing such various chlorinated organic compounds as described above from a fluid such as a waste gas and wastewater and at the same time it is also urgent to establish a technique of analysis of such chlorinated organic compounds contained in a fluid in global scale.
At the time of analyzing chlorinated organic compounds contained in a fluid, at first, a sample has to be taken precisely and accurately from a fluid to be an object for the analysis. For example, in the case of analysis of chlorinated organic compounds contained in a waste gas, a prescribed amount of a sample gas is sampled from a space containing the waste gas, for example, a flue duct, to pass the waste gas through. Various chlorinated organic compounds contained in the sample gas are required to be reliably collected without leakage. Especially, since dioxins and coplanar PCBs, environmental pollutants as described above, are contained in extremely slight amounts in the sample gas, and regardless of the existing form, such as particulate form or gaseous form, the types of pollutants vary widely, failing precise sampling. Thus, highly reliable analysis results cannot be expected. Further, the above-described coplanar PCBs is contained in a large amount in the atmospheric air, and if the sample gas is contaminated with such coplanar PCBs, highly reliable analysis results is not expected. For that, in order to guarantee the accuracy of the analysis results, Japan, US, and each country of Europe, respectively, have been officially regulating the sampling methods of samples necessary to analyze the chlorinated organic compounds such as dioxins and coplanar PCBs contained in, for example, a waste gas.
For example, the Japanese Industrial Standards JIS K 0311: 1999 formulated on Sep. 20, 1999 regulates, “A measurement method of dioxins and coplanar PCBs in waste gas” and practically exemplifies a sampling apparatus of a sample gas containing chlorinated organic compounds such as dioxins. The sampling apparatus is provided with a sampling tube for sampling a sample gas from a flue duct in which a waste gas of an incinerator flows through, a first collector equipped with a filter unit for sampling the chlorinated organic compounds mainly in a particulate form contained in the gas sampled in the sampling tube, and a second collector for sampling the chlorinated organic compounds in a gaseous form difficult to be sampled by the first collector. In this case, the second collector is provided with mainly a liquid collecting section composed of a plurality of impingers made of glass and filled with an absorption liquid and an adsorptive collecting section containing an adsorbent (e.g. XAD-2) so as to collect the chlorinated organic compounds in the gaseous state, which are not collected by the first collector, by the absorption liquid and the adsorbent.
Such a sampling apparatus has a complicated constitution comprising the first collector and the second collector and is costly owing to the use of many appliances made of glass, so that in many cases, the apparatus is used repeatedly. In such a case, since it is required to keep the respective members such as impingers clean in order to retain the reliability of the measurement data, the preparatory operation such as a washing work and the like to be carried out before sampling of a sample gas becomes extremely complicated. Further, at the time of sampling the gaseous chlorinated organic compounds contained in the sample gas by the second collector, the second collector is required to be cooled by a cooling material such as dry ice and the sample-sampling operation itself becomes extremely complicated, too. Further, after the sampling of the sample gas, the chlorinated organic compounds collected by the first collector and the second collector are needed to be extracted and in this case, the chlorinated organic compounds separately collected by the first collector and the second collector are needed to be extracted separately. Therefore, the extraction operation itself becomes complicated and takes a long time to finish and further the reliability of the analysis results is, in many cases, affected by the skills of the extraction operation. Further, the sampling apparatus comprises two types of collectors, the first collector and the second collector, so that the apparatus is inevitably enlarged, and also glass appliances are used a lot, therefore the apparatus is easy to be broken to make handling and transportation difficult at the time of sampling the sample gas.
On the other hand, the Environment Preservation Agency (EPA) of the U.S. and the Comite de Europeen Normalisation (CEN) have determined official methods independently, and the sampling apparatuses described therein are not so much different from the Japanese one described above in terms of the complication of the constitution and the difficulty of handling, although there exist minor detailed differences.
The object of the present invention is to simultaneously collect and sample various kinds of chlorinated organic compounds in both particulate form and gaseous form and easily extract the sampled chlorinated organic compounds.